Metal nanoparticles coated with molecules such as proteins can be used to determine binding events by monitoring a change in optical properties of the particles, such as by Localized Surface Plasmon Resonance (LSPR) sensing. In the common scheme a recognition interface is constructed on the metal nanostructure. The specific binding of an analyte to said recognition interface is converted into an optical signal, e.g. a change in absorbance (wavelength, intensity) which is detected and analyzed.
LSPR sensing is based on the sensitivity of the localized plasmon absorbance of metal nanoparticles to changes in the dielectric properties of the contacting medium.
In principle LSPR can be used in the detection of antibody-ligand interactions, receptor-ligand interactions, enzyme-ligand binding and antibody-antigen association-dissociation kinetics.
In practice, however it is observed that such methods where nanoparticles are used in solution often do not attain the required accuracy.
Thus, there remains a need in the art to provide methods which allow the accurate determination of interactions between molecules using nanoparticles.